Red Flags
- Hot swollen joint with fever — exclude septic arthritis (joint aspiration); empirical antibiotic until ruled out[1]
- Locked knee, sudden inability to extend, or trauma — orthopaedic review for meniscal tear, loose body, or fracture[1]
- Inflammatory arthritis features (early morning stiffness >60 min, multiple small joints, systemic features) — rheumatology workup[1]
- Severe disabling pain refractory to conservative therapy with end-stage radiographic OA — orthopaedic surgical evaluation[1]
First-line treatment
Interventions
- Education, self-management, lifestyle change[1]Cornerstone of management; structured patient education, activity modification, joint protection; community programmes (osteoarthritis schools); arthritis self-management courses
- Weight reduction (BMI ≥25)[1]5–10% weight loss reduces knee pain and improves function; meaningful at any BMI; combined dietary and exercise approach
- Structured exercise — strengthening + aerobic[1]Quadriceps strengthening, range-of-motion exercises, low-impact aerobic (walking, swimming, cycling), tai chi, yoga; supervised programme initially then home maintenance; equally effective regardless of severity
- Bracing, footwear, and orthoses (selected)[1]Knee brace for medial OA with varus deformity; appropriate footwear; lateral wedge insoles inconsistent benefit; walking aids for severe disease
- Avoid ineffective therapies[1]Routine glucosamine and chondroitin not recommended; arthroscopic lavage and debridement no benefit (NICE, AAOS, OARSI); avoid intra-articular hyaluronan as routine (mixed evidence)
First-line drug therapy
| Drug | Class | Adult | Paediatric | Notes |
|---|---|---|---|---|
| Topical NSAID (diclofenac gel, ketoprofen)[1] | Topical NSAID | Apply 2–4 g to affected knee 3–4× daily | — | First-line topical for knee OA; comparable efficacy to oral NSAID with much lower systemic exposure; preferred in elderly and CKD |
| Paracetamol[1] | Analgesic | 1 g PO QDS PRN, max 4 g/day | — | Limited efficacy in OA per recent reviews; useful adjunct or when NSAID contraindicated; lowest effective dose |
| Oral NSAID (naproxen, ibuprofen, celecoxib)[1] | Cyclooxygenase inhibitor | Naproxen 250–500 mg PO BD; ibuprofen 400 mg PO TDS; celecoxib 200 mg PO daily | — | Lowest effective dose, shortest duration; co-prescribe PPI if GI risk; avoid in CKD G3+, peptic ulcer, severe HF, anticoagulation; selective COX-2 if GI risk |
| Intra-articular corticosteroid[1] | Glucocorticoid injection | Methylprednisolone 40 mg or triamcinolone 40 mg intra-articular; max 3–4× per year per joint | — | Useful for moderate-severe pain flare; effect 4–8 weeks; transient post-injection flare; chondrotoxicity with repeated injections |
| Duloxetine[1] | SNRI antidepressant | 30 mg PO daily, titrate to 60 mg | — | Adjunct for moderate-severe OA pain refractory to first-line; analgesic effect at 4–6 weeks; useful with comorbid depression/chronic pain |
| Tramadol (selected, short-term)[1] | Atypical opioid / SNRI | 50–100 mg PO every 4–6 h, max 400 mg/day | — | Reserve for moderate-severe pain refractory to first-line; constipation, dizziness, dependence concerns; avoid long-term |
Topical NSAID (diclofenac gel, ketoprofen)[1]
Topical NSAID
- Adult
- Apply 2–4 g to affected knee 3–4× daily
- Paediatric
- —
First-line topical for knee OA; comparable efficacy to oral NSAID with much lower systemic exposure; preferred in elderly and CKD
Paracetamol[1]
Analgesic
- Adult
- 1 g PO QDS PRN, max 4 g/day
- Paediatric
- —
Limited efficacy in OA per recent reviews; useful adjunct or when NSAID contraindicated; lowest effective dose
Oral NSAID (naproxen, ibuprofen, celecoxib)[1]
Cyclooxygenase inhibitor
- Adult
- Naproxen 250–500 mg PO BD; ibuprofen 400 mg PO TDS; celecoxib 200 mg PO daily
- Paediatric
- —
Lowest effective dose, shortest duration; co-prescribe PPI if GI risk; avoid in CKD G3+, peptic ulcer, severe HF, anticoagulation; selective COX-2 if GI risk
Intra-articular corticosteroid[1]
Glucocorticoid injection
- Adult
- Methylprednisolone 40 mg or triamcinolone 40 mg intra-articular; max 3–4× per year per joint
- Paediatric
- —
Useful for moderate-severe pain flare; effect 4–8 weeks; transient post-injection flare; chondrotoxicity with repeated injections
Duloxetine[1]
SNRI antidepressant
- Adult
- 30 mg PO daily, titrate to 60 mg
- Paediatric
- —
Adjunct for moderate-severe OA pain refractory to first-line; analgesic effect at 4–6 weeks; useful with comorbid depression/chronic pain
Tramadol (selected, short-term)[1]
Atypical opioid / SNRI
- Adult
- 50–100 mg PO every 4–6 h, max 400 mg/day
- Paediatric
- —
Reserve for moderate-severe pain refractory to first-line; constipation, dizziness, dependence concerns; avoid long-term
Safety-net
- Daily quadriceps exercises and weight reduction are the most powerful long-term treatments — combine with simple analgesia[1]
- Avoid prolonged use of oral NSAIDs and opioids — topical NSAIDs are safer for daily use[1]
- Hot swollen joint, fever, sudden inability to bear weight, or red spreading skin — same-day medical review (rule out septic arthritis)[1]
Referral criteria
- Septic arthritis suspicion, locked knee, or significant traumaEmergency orthopaedics[1]
- Severe disabling pain refractory to ≥3 months conservative therapy with end-stage radiographic OAOrthopaedic surgery for arthroplasty (TKR or UKA) or osteotomy in selected younger active[1]
- Inflammatory features or suspected non-OA aetiology (rheumatoid, gout, psoriatic, septic)Rheumatology[1]
- Ongoing functional impairment despite optimal medical managementMultidisciplinary OA clinic with physiotherapy, OT, weight management[1]
Clinical summary
Diagnosis, lifestyle, pharmacological and surgical management of knee osteoarthritis in adults.